There are a great many different types of telephone systems in widespread use. For example there are conventional telephone systems, generally referred to as Plain Old Telephone Service (POTS) systems. There are cellular telephone systems that provide connections by various radio frequency protocols. Other modern telephone systems utilize Voice Over Internet Protocol (VOIP) technology. The specific preferred embodiments described herein related to VoIP systems; however, it should be understood that other embodiments are possible using other types of telephone systems;
In general, there are two types of telephone calls. In the first and most common situation, there is a single calling party and a single called party. In the second type of call, generally referred to as a conference call, a number of parties are connected together.
Calls other than conference calls, have a single calling party and a single called party. In the simplest situation, if a call is placed to a telephone that is busy with a first call, the calling party merely receives a busy signal and no indication concerning the first call is given to the calling party. Features such as call waiting and caller ID provide the called party with an indication that someone is trying to reach them. However, the calling party is given no significant information other than a ring tone or a busy signal.
Voices over IP (VOIP) telephones are gaining popularity. There are many different varieties of VOIP telephones commercially available. Many VOIP telephones include a display that includes “soft keys”. Soft keys are keys that can be programmed to provide a variety of functions. The embodiments of the invention described below utilize such soft keys. However, it should be understood that the soft keys are merely one mechanism for sending signals from a handset to the device controlling the handset. A wide variety of other such mechanisms are available.
When a call is placed over any type of telephone system, the user who places the call and the users who is called are provided with various information. For example, if the called telephone is busy, a busy signal is generally sent to the party that placed the call. In other systems, when a called telephone is busy, the calling party is connected to a voice mail system. A party who calls a line that is busy, may hear a busy signal, or hear various types of messages, but such a caller is not given information abut the call that is in progress.